Surgical procedures are regularly performed using "sets" of pre-selected surgical instruments, each set being a collection of instruments established from experience to be useful in a given surgical procedure. For example, the surgical instruments expected to be used in an obstetrical procedure are grouped together to form a set and, as a set, are sterilized, stored on a pan or tray, and finally transported on that tray to the operating room when their use is required.
Sterilization of reusable and delicate, precision surgical instruments and their subsequent sterile storage is of paramount concern to surgeons and hospitals. Sterilized surgical instruments are essential during surgical procedures to minimize coming in contact with a suitable medium, may incubate to harmful levels. Condensation remaining after sterilization, either in the tray or on the instruments, provides such a medium for the growth of deleterious bacteria during the subsequent storage of the sterilized instruments.
Some example prior art patents which provide for sterilization containers are Arp et al, U.S. Pat. No. 4,643,303, Nichols, U.S. Pat. No. 4,728,504, and Spence, U.S. Pat. No. 4,783,321. These prior art patents generally teach the use of baskets or trays to hold the instruments to be sterilized, and apertures in the baskets which allow for gross drainage of condensation from the baskets to the container floor below the basket. The condensation then must again drain from the container floor. This double drainage increases the risk of condensation remaining in proximity to the sterilized instruments and the subsequent contamination of the condensation by airborne bacteria. These prior art baskets or instrument retention devices are of such design that excessive condensation may be trapped between the instruments and the device.
Many prior art patents have no separate container locking device to provide a sealing effect between the container halves. Thus, the flow of steam or other gaseous sterilants during the sterilization is not firmly restricted to the apertures. More sterilization, thus increasing the risk of airborne bacterial contamination of any remaining condensation.
U.S. Pat. No. 4,643,303 describes a sterilization container enclosing an instrument basket within a box-like base and cover. The container also includes clamps mounted to the container by hinges for releasably holding the cover to the base, U.S. Pat. No. 4,783,321 describes a sterilization container enclosing an instrument basket within a base and cover. The container also includes a latch mechanism for releasably holding the cover to the base.
Most of the prior art, for example, Nichols U.S. Pat. No. 4,728,504, provide for the placement of the instruments on a removable basket or tray which includes apertures formed on the bottom of the tray to allow for the drainage of condensation. The domed configuration of the tray bottom in U.S. Pat. No. 4,728,504 allows for sufficient surface area contact with the instruments such that condensate may be held between the instruments and the tray after sterilization. Such a risk of airborne bacterial contamination of remaining condensation after sterilization increases during increased storage of the sterilized instruments. Thus, it is imperative to remove as much condensation as possible from the container and from the instruments after sterilization.
Hauze, U.S. Pat. No. 4,798,292, describes a non-locking sterilization container with apertures arranged in rows and columns enclosing a flat surfaced insert with apertures arranged in rows and columns such that the apertures in the container and the insert are vertically aligned. Pegs are inserted in the insert apertures to provide horizontal separation of the instruments during sterilization and subsequent presentation of the instruments. The flat surface of the insert and the pegs increase the risk of condensation remaining in proximity to the instruments after sterilization.
The foregoing discussion of the prior art was taken from Brooks, U.S. Pat. No. 5,098,676 which describes an improved sterilization tray assembly for sterilizing, transporting and storing instruments, which overcomes the aforesaid and other disadvantages of the prior art. Brooks provides a sterilization tray assembly comprising an upper tray section including a plurality of upper tray ports spaced in a predetermined pattern; a lower tray section including a plurality of lower tray ports spaced in a predetermined pattern; and locking means for engaging the upper tray section and the lower tray section to form a sealing contact between the upper and lower tray sections. A mat made of silicone rubber and sized to fit the tray is positioned between the tray sections. The mat has an upper surface and a lower surface, and includes a plurality of ports in the mat spaced in a predetermined pattern wherein the mat ports and the lower tray ports are in vertical alignment. The mat also has a plurality of upwardly tapered, vertical projections spaced in a predetermined pattern on the upper surface, the vertical projections having tips at their free ends to provide support for instruments above the upper surface; and a plurality of downwardly projecting support feet depending from the lower surface spaced in a predetermined pattern for spacing the lower surface above the lower tray section.
The sterilization tray assembly as described in U.S. Pat. No. 5,098,676 is available commercially from PolyVac, Inc. of Manchester, N.H., and has achieved substantial commercial success. However, the spring locking hinges as described in U.S. Pat. No. 5,098,676 may not always be adequate, particularly in the case of large sterilization trays which may become quite heavy when loaded. Also, while the silicone rubber mat as described in U.S. Pat. No. 5,098,676 provides a convenient support for larger surgical instruments; smaller instruments may not be securely held. Accordingly, PolyVac, Inc. and others have introduced sterilization trays including one or more holding strips specifically designed to releasably hold selected surgical instruments.
The present invention is an improvement over the sterilization, transporting and storage container trays such as described in U.S. Pat. No. 5,098,676.